Purpose <p>Semi-active suspension systems have been adopted to address ride comfort and vehicle stability to offer improved adaptability.</p> Methods&#xa0; <p>This study proposes a control strategy for a quarter-car semi-active suspension system based on linear quadratic regulator with integrator. An additional state is introduced to represent cumulative suspension dynamic travel, thereby enhancing control over prolonged motion and eliminating steady-state error. Particle swarm optimization is employed to tune the weighting matrices of the proposed controller. Actuator saturation constraints are incorporated into the controller design to maintain stable operation within allowable input limits. The proposed strategy is evaluated through simulations under varying road conditions using key performance indicators including the root mean square values of sprung mass acceleration, suspension dynamic travel, tyre load, and tyre deflection.</p> Results&#xa0; <p>The controller is further tested across three different quarter-car models to validate applicability of the proposed controller. Comparative analysis demonstrates that the proposed controller outperforms existing methods including proportional integral derivative, Fractional order proportional integral derivative, Fuzzy proportional integral derivative, Fuzzy dung beetle optimizer with proportional integral derivative, linear quadratic regulator with particle swarm optimization, passive suspension systems, and fuzzy grey wolf optimizer with proportional integral derivative. The proposed approach shows improved performance across different suspension configurations and road profiles compared to conventional and intelligent control strategies.</p> Conclusion&#xa0; <p>By reducing vibration exposure and maintaining consistent tyre-road contact, smoother rides can be achieved in vehicles.</p> Graphical Abstract <p></p>